Voltage surge suppressors for the protection against overvoltages and the overcurrents resulting therefrom are widely used in telecommunication applications. They conventionally comprise an electrode arrangement in a capsule of glass or ceramics filled with an inert gas, such as neon or argon. Such a voltage surge suppressor acts as a voltage-dependent switch forming an arc of high current carrying capability (approx. 2.5 kiloamps to 20 kiloamps) after exceeding the type-dependent ignition voltage. However, these voltage surge suppressors may exhibit aging problems, depending on the duration of use and on the type of the load. A typical problem is the loss of inert gas in the capsule and an increase in replacement thereof by air. Thereby, the response voltage of the voltage surge suppressor is increased such that it will be a multiple (approx. 2,500 to 5,000 volts) of the standard value. It is required therefore, that an additional protection ensuring a certain maximum response voltage be provided. This is commonly in the order of 1,000 to 1,500 volts.
Such a protection can be achieved by a disconnecting spark gap in air. With electrode distances between 0.1 and 0.5 mm response voltages of 0.2 to 0.5 kilovolt can be obtained. These additional disconnecting spark gaps require, however, different geometrical dimensions of the voltage surge suppressor and thus a deviation from the standard sizes; further, the manufacturing costs are increased in a non negligible way.
From DE 38 13 889 C1 there is known in the art a connector or disconnector bank for the telecommunication technique. Onto this bank there can be plugged at least one voltage surge protection plug having a housing wherein there is disposed a voltage surge suppressor.